The device (1) is intended to be applied to or adjacent to a patient's peribucal zone and comprises a generating member (10) of a gaseous fluid flow exerting a barrier effect between an inner area of the patient's mouth and the outside of the mouth； and a support (11) of said generating member (10) of a gaseous fluid flow, keeping it arranged in an area proximate said peribucal zone, wherein the generating member (10) is formed by at least one duct that includes at one of its ends an aperture (12) which is disposed outside the peribucal zone in front of said support (11).
